Cooling agent dispenser



April 1946- D. R. DOUSLlN ET AL 2,399,334

COOLING AGENT DISPENSER Filed July 26, 1943 2 Sheets-Sheet 1 TO COMPRESSED MRLJNE uoum AIR

OVERHEAD COOLING FAKE-OFF ZONE V l"as FRACWONNHNG COMPRESSED LU AIR-LINE 3 1 17 u 12 FLOATING NEEDLE vAum Am VENT METER STICK lo 3 m ,/MERCURY ,19 BOA. \CONSTRICTION F/G. Z

INVENTORS D.R. DOUSLIN C.F. WEINAUG F/G. I WWfW ATT EYS April 30, 1946.

D. R. DOUSLIN ET AL COOLING AGENT DISPENSER Filed July 26, 1943 2 Sheets-Sheet 2 INVENTORS D. DOUSLIN C. F. WEINAUG Patented Apr. 39, 1946 M if s'rATEs COOLING AGENT DISPENSER Donald R. Douslin and Charles F. Weinaug,-

Bartlesvillc, kla., assignors to Phillips Petroleum Company, a corporation of Delaware Application July 26, 1943, Serial No. 496,204

Claims.

' in connection with automatic pressure control of a low-temperature low-pressure analytical fractionating column.

In some respects, the present invention is an improvement on the patent to W. J. Podbielniak No. 1,967,258, issued July 24, 1934. The arrangement described by Podbielniak includes a control device which is adapted to maintain a constant pressure in the column. A manometer which is connected with the vapor outlet tube by a side arm is provided with electrodes leading to an electrical circuit which includes a solenoid valve. The valve controls the effective pressure applied from a source of constant air pressure to a body of liquid air in a flask. In the operation of the Podbielniak arrangement, pressure increase in the fractionating column is registered on the mercury column of the manometer, closing the circuit through the solenoid valve and applying pressure to the liquid air which is forced into the cooling section of the column, thereby reducing the fractionation pressure. Our invention is a manifest improvement over the arrangement of the patent in providing fully automatic control of the fractionating pressure in an advantageous and expedient manner and with the elimination of involved electrical circuits, solenoid valves and other relatively expensive equipment which have heretofore been considered essential to the operation of such devices.

This application is a continuation in part of the subject matter of application, Serial No. 468,148, filed December 7, 1942, by Donald R.

Douslin in that liquid air container and dispenser 6 has been improved and this improvement is in effect also an improvement of the entire combination.

One of the difiiculties of the prior art method and apparatus was that the liquid cooling agent would vaporize all along the tube and form a finer control on the amount of cooling agentdelivered.

A further object is to provide constant flow of small slugs of cooling agent as distinguished from the tendency of prior art devices to suddenly surge over an excessively large slug. The result of constant flow or small slugs is obviously a more constant temperature in the cooling zone and thereby a more constant pressure in the fractionating column; and it is an object of the invention to provide this more constant pressure and to avoid any violent surges in'fiuids, in temperatures and in pressures.

It is also an object of the invention to maintain the pressure wtihin the cooling agent container, as opposed to the quick pressuring of the prior art, which quick pressuring isproductive of large slugs. v

Still another object is to prevent moisture from freezing and plugging the intake line 1.

Further objects are to provide a simple ,foolproof embodiment of the invention; other objects will be apparent to those skilled in the art from the construction of this illustrative embodiment of the invention as described in the specification,

- claimed in the claims and shown in the drawings,

in which:

Figure 1 is a general view of an analytical fractionating column and manometer incorporating our improvement.

Figure 2 is a sectional detailof the valve control shown in Figure 1.

Figure 3 is an elevational view mainly in cross section of an illustrative embodiment ofthe improved liquid air dispensing container forming part of the invention.

With specific reference to Figure l, l is an analytical iracionating column ofthe general type described in Podbielniak Patent 1,967,258. having heating element 2 and a cooling zone 3 forming a receptacle at the top of the column provided with an outlet 4 and inlet conduit" 5 connected with a supply 6 of liquid air or nitrogen, which is adapted to be forced by compressed air pressure throughconduit 1 into the cooling section in an amount proportionate to pressure variation in the fractionating column in a manner hereinafter described. The overhead vapors from the fractionating process pass through conduit 8 to an accumulator not shown. Conduit 8 is provided with a side arm 9 which connects with a mercury manometer l0 fixed to the meter stick I I. The arm IOA of the manometer connects with conduit I and is provided with a-floating needle valve designated generally at 12 in Figure l and shownin detailin Figure 2. As clearly shown in Figure 2, arm I on is vented to the atmosphere through air vent l3 and has an elongated relatively restricted section I! through which the head l5 of the needle valve will barely pass. The needle valve may be formed of any suitable material either solid or hollow according to the specific gravity of the manometer fluid, the main prerequisite being that it floats on the body of fluid in the column. In the present application we prefer to construct the needle valve of solid glass with an enlarged lower portion for contact with the manometer fluid. A constriction I6 is provided in the arm IUA to limit the downward movement of the needle valve.

Any low. boiling point liquid, or other known liquid cooling agent may be employed if it will produce the desired degree of low temperature.

The arm IRA is provided with a side arm l1 connected with a source of air under constant pressure. It will be understood that the inside diameter of the restricted portion ll of the arm 10A is slightly greater than the outside diameter of the needle valve head l5, so as toallow a con t-inuous small flow of air through the vent, the magnitude of which is dependent on the position of the needle valve l2. A leveling bottle 18 having a pinch clamp 19 is connected with the manometer tube III at the bend thereof.

In operation, heat is applied to the bottom of the fractionating column and overhead vapors pass through the line 8 to the accumulator, not shown. The pressure variation in the fractionating column is registered on the manometer column fluid which causes the needle valve to rise and fall relative to the restricted portion ll. The quantity of air under constant pressure from air line 11 passing head to the vent l3, and likewise the pressure imposed on the liquid air supply 6, is therefore, a function of the pressure in the fractionating column. It is therefore obvious that increase of pressure in the fractionating column will force an increased quantity of liquid air into the cooling zone 3 reducing the pressure in the column. During normal operation and while the pressure in the column is constant a small quantity of liquid air is continuously forced into the cooling zone. By regulation of the compressed air pressure admitted at H and by adjusting the mercury level with the leveling bottle [8, it is possible to fractionate under any desired constant pressure automatically and without attention of the operator.

Figure 3 is an enlarged view of the liquid cooling agent container and dispenser 6 and related parts of Figure 1. Figure 3 shows in detail the electrical connections and heating elements 22 and21 preferably employed in practicing the invention.

Container 6 may be a double-walled Dewar flask with a vacuum chamber between the walls and we prefer to use any inexpensive thermos bottle as this container. A single-walled container could be used and container 6 is so shown i or purposes of simplicity.

Compressed air from line H passes through pipe 1 and out end 32 into chamber 6. The compressed air forces the liquid cooling medium into the bottom of pipe 3| and up to the heating filament 21. Heating filament 21 causes the liquid cooling agent to vaporize in'fiashes forcing small slugs of liquid cooling agent through pipe 5 to cooling zone 3 as will be explained in detail later. Pipes 1 and 5 pass through a rubber stopper 3!! which tightly fits the top of the container 6. Wires 28 and 28 pass through or alongside stopper 30 and are sealed by rubber stopper 8!! so that the only passage for fluids is in pipe 1 and out pipe 5.

A power line 2|! is tapped by wire 2| for electric current to heat resistance wire 22 wound around pipe 1. The circuit is completed by wire 23 the amount of current being controlled by rheostat 24 the electricity returning to the other 25.

A similar lead 26 from power wire 20 carries current through heating wire 21 and wire 28 to rheostat 29 and power wire 25.

The operation of the device is as follows:

The container 6 is filled with a liquid cooling agent and the connections at the stopper 30 of the container is made air tight. Pressuring fluid, such as compressed air, is admitted through tube 1 from device l2, 11 which controls the admittance of the pressuring fluid. The increase of pressure within container 6 causes the liquid cooling agent to rise up through tube 3| and contact heating element 21 which heating element is much power line hotter than the cooling agent. When this con-- tact is made, a flash vaporization of a small amount of the cooling agent forces a small slug of unvaporized cooling agent out through tube 6 which leads to cooling zone 3 of fractionating column I. When the cooling agent which was in contact with element 21 is forced out of tube 5 as explained, more cooling agent will rise out of container 6 through tube 3| to contact heating element 21 as before. This action as described creates a succession of small slugs of cooling agent from tube 5 the size of these slugs being determined by the quantity of heat delivered by heating element 21 and by the pressure within the container.

The quantity of heat delivered by heat element 21 is controlled by rheostat 29. The pressure within the container Sis controlled by floating needle valve l2 and other related parts shown in Figure 2.

The heater at 22 warms the pressuring fluid as it comes in through tube 1 and prevents collection of water to any great extent from the water vapor which may be present in the compressed air and also positively prevents freezing of this water in tube 1. When other pressuring fluids are used other types of condensible and 'solidiflable material are prevented from forming by heater cooling medium in heat exchange relationship with the upper portion of said column, a vapor outlet line leading from said column, means responsive to the degree of pressure change in said outlet line controlling the amount of cooling medium supplied the upper portion of said column, and direct heat exchange means in the means supplying the cooling medium for dividing the cooling medium into slugs.

2. In apparatus for fractional distillation, a distilling column and means for applying heat to the lower portion thereof, means ior supplying a cooling medium in heat exchange relationship with the upper portion 01 said column, a vapor outlet line leading from said column, a body of fluid responsive to the degree of pressure change in said outlet line, a valve floating on said fluid and variable in response to movement thereof to control the amount of cooling medium supplied the upper portion of said column, and direct heat exchange means in the means supplying the coolin; medium for dividing the cooling medium into slugs.

3. In apparatus for fractional distillation. a distilling column and means for applying heat to the lower portion thereof, means for supplying a cooling medium in heat exchange relationship with the upper portion of said column, a vapor outlet line leading from said column, a manometer having one arm connected with said outlet line, a variable opening valve responsive to fluid movement in the other arm controlling the amount of cooling medium supplied the upper portion of said column, and direct heat exchange means in the means supplying the cooling medium for dividing the cooling medium into slugs.

4. An apparatus for dispensing slugs of a liquid cooling agent comprising in combination a Dewar flask, a source of pressure fluid comprising an inletconduit entering said Dewar flask, an outlet conduit leaving said Dewar flask, and electrical heating means heating said outlet conduit to a degree causing slug formation, and an eiec-.

trical control system, said control system comprising a power line, a circuit from the power line through said electrical heating means, and a rheostat in the circuit whereby the temperature of the heating means may be controlled.

5. An apparatus for dispensing slugs of a liquid cooling agent comprising in combination a Dewar flask, a source 0! pressure fluid comprising an inlet conduit entering said Dewar flask, an outlet conduit leaving said Dewar flask, electrical heating means heating said inlet conduit, and electrical heating means heating said outlet conunit to a degree causing slug formation, and an electrical control system comprising a power line, separate circuits from the power line through each electrical heating means, and a rheostat in each circuit whereby the temperature of the re spective heating means may be controlled.

. DONALD R. DOUSLIN.

CHARLES F. WEINAUG. 

